In accordance with rapid aging of the population in recent years, there are increasing needs for welfare assistive devices that support caring of aged persons in the field of welfare. The most burdensome work in the field of caring is moving a cared person or adjusting the posture of the cared person. Much attention is paid to care-oriented power assisting devices that alleviate a load applied on the muscle force of a caregiver who makes such movement or adjustment.
For example, Japanese Unexamined Patent Publication No. 2000-51289 (Tokukai 2000-51289; published on Feb. 22, 2000) discloses a care-oriented power assisting device that functions with use of an air pressure actuator having a light weight and a small size.
Further, Japanese Unexamined Patent Publication No. 2004-105261 (Tokukai 2004-105261; published on Apr. 8, 2004) discloses a power assisting instrument with a downsized structure that alleviates a load applied on human muscles.
Other examples of power assisting devices include BLEEX developed by Kazerooni et al. of University of California and HAL manufactured by Sankai et al. of University of Tsukuba.
Furthermore, International Application Publication (International Publication 2006/092872 pamphlet; published on Sep. 8, 2006) discloses a driving force calculating device capable of calculating a driving force that allows a desired load to be applied on a muscle at a time when a power assisting device aids/prevents a predetermined motion.
These power assisting devices are also effective for muscle training with alleviated or added loads on muscles in the field of sports engineering and rehabilitation engineering.
In order to develop a new method for evaluating athletic abilities or a new rehabilitation method, much studies have been made in the field of sports engineering and rehabilitation engineering as to estimation of muscle activities of humans in motion.
For example, Japanese Unexamined Patent Publication No. 1995-313495 (Tokukaihei 7-313495; published on Dec. 5, 1995) discloses a technique in which athletic properties of a subject who operates an exercise device are measured, and inverse analysis is used to estimate the muscle force of a living body.
Examples of commercially available software for estimating the muscle force of a living body that performs a certain motion include “ARMO” that is a 3 D muscle simulator manufactured by Gsport Inc., and “SIMM” that is a musculoskeletal model of a whole body manufactured by Musculographics Inc.
It is desirable that a power assisting device worn by a caregiver allows individual regulation of loads applied on respective muscles in consideration of muscular properties, in order that unnatural loads are not applied on the caregiver.
Further, in order to increase a rehabilitation effect for a handicapped person, it is desirable to classify individual muscles into muscles on which loads are to be applied and muscles on which loads are not to be applied, and regulate loads applied on the individual muscles so as to selectively assist the muscles on which loads are not to be applied. Equally, it is desirable to selectively apply loads on the muscles on which loads are to be applied in muscle training.
However, neither of Japanese Unexamined Patent Publication No. 2000-51289 and Japanese Unexamined Patent Publication No. 2004-105261 disclose a technique for regulating each of loads applied on individual muscles while a power assisting device assists a predetermined motion. Further, BLEEX and HAL as mentioned above do not have a mechanism for regulating each of loads applied on individual muscles.
In contrast, applying the driving force calculating device disclosed in International Publication 2006/092872 pamphlet to a power assisting device would allow regulating each of loads applied on individual muscles at a time when a user performs a predetermined motion. The driving force calculating device operates as follows: the user enters a target muscle force to be generated for a particular muscle, and a driving force of a driving section (artificial muscle) of a power assisting device is calculated based on the target muscle force and torque of a joint that is necessary for the predetermined motion.
However, in a case of using the driving force calculating device, it is necessary to enter a target muscle force not only for a muscle to be aided by the power assisting device but also for a muscle not to be aided by the power assisting device. Furthermore, when a combination of muscle forces calculated by the driving force calculating device is much different from a target value, it is necessary to reset the target muscle force.
Therefore, the driving force calculating device has problems such that it takes much time to calculate the driving force of the driving section of the power assisting device and that the calculation does not always results in a suitable driving force.